Electric double-layer capacitors (EDLCs), commonly referred to as supercapacitors or ultracapacitors (herein referred to as ultracapacitors), may be used for a wide variety of applications, e.g., as a power source for electric and/or hybrid machines, as a power source for various electronic devices, etc. A single ultracapacitor cell generally has a working voltage between approximately 0 and 3 volts. Thus, to achieve higher voltages, multiple ultracapacitor cells may be connected in series as an ultracapacitor module. Moreover, multiple ultracapacitor modules may also be connected in series to form an ultracapacitor pack and achieve yet a higher voltage.
When using ultracapacitors for power applications as discussed above, it may be desirable to detect problems occurring with one or more ultracapacitor cells within the ultracapacitor pack. For example, it may be desirable to detect whether an ultracapacitor cell is short-circuited because a short-circuited cell may lead to decreased performance or pose safety concerns such as potential fire hazards.
An exemplary system that may be used to determine certain conditions within an ultracapacitor, such as a short-circuited ultracapacitor cell, is disclosed in U.S. Pat. No. 7,633,284 to Ingram et al. that issued on Dec. 15, 2009 (the '284 patent). The system in the '284 patent measures parameters such as the voltages of each individual ultracapacitor cell and determines certain conditions such as cell short circuits based on the individual cell measurements. Although the system of the '284 patent may be useful for detecting an ultracapacitor cell short circuit, the system may be unnecessarily costly, large, and complex due to the hardware and software requirements associated with measuring the parameters of each individual cell.
The disclosed machine implement control system is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.